Things that could be limiting your ability to get there:

• Limited shoulder flexion (short/stiff lats, long head of triceps, teres major, inferior capsule)
• Limited shoulder external rotation (short/stiff pecs, lats, subscapularis)
• Lack of scapular upward rotation (weakness of lower traps, upper traps, and/or serratus anterior; and dominance of levator scapula, rhomboids, and pec minor)
• Poor thoracic spine extension
• Lack of anterior core stiffness

With all these potential problems, chances are that improving each just a little bit will yield big results, especially since they interact with each other on a number of fronts.  For instance, if you reduce stiffness in your lats, your anterior core won’t have to work quite as hard to overpower that stiffness, so its relative stiffness improves.

Below, you’ll find videos of exercises you’ll want to incorporate in your warm-ups daily to gradually build up your range-of-motion and overhead stability.